Develop Reference

How to add an object to an array of object, using addToSet, or push operators in mongodb

I have an array of reviews, I want to add a review using addToSet that will check if user is present in the array, then we do not want to add since one user can only review once.
My schema looks like this:
const sellerSchema = new mongoose.Schema({
user: {
type: mongoose.Schema.Types.ObjectId,
ref: "User",
unique: true,
},
reviews: [
{
by: {
type: mongoose.Schema.Types.ObjectId,
ref: "User",
unique: true,
},
title: {
type: String,
},
message: {
type: String,
},
rating: Number,
imagesUri: [{ String }],
timestamp: {
type: Date,
default: Date.now,
},
},
],
});
I might be doing the query wrong, but can't figure out how to add a review and check if current user has not reviewed before.
Here is the query where I add the review:
router.post("/review/:_id/", async (req, res) => {
try {
const stylist_id = mongoose.Types.ObjectId(req.params._id);
const review = {
by: req.user._id,
title: req.body.title,
message: req.body.message,
rating: parseFloat(req.body.rating),
};
if (req.body.imagesUri) {
//if there is images, we need to set it up
review.imagesUri = req.body.imagesUri;
}
await Seller.updateOne(
{ _id: seller_id },
{ $addToSet: { reviews: review } } //get the review that matches to the user_id
);
return res.status(200).send(true);
}catch(err){
res.status(502).send({
error: "Error creating a review.",
});
}
});
I'm thinking of checking for seller's id and also check that no review is by current user, but it is not working.
const userID = req.user._id;
await Seller.updateOne(
{ _id: seller_id, reviews: { $elemMatch: { by: { $ne: { userID } } } } },
{ $addToSet: { reviews: review } } //get the review that matches to the user_id
);
ANSWER:
I was able to solve the issue, in case other people have same issue. I did this:
await Seller.updateOne(
{
_id: seller_id,
"reviews.by": { $nin: [req.user.id] },
//knowing req.user._id is a mongoose.Types.ObjectId.
//You can also use [id1, id2, ...] to the array to check for other id's
},
{ $addToSet: { reviews: review } } //get the review that matches to the user_id
);
Here is the documentation for $nin operator: https://www.mongodb.com/docs/manual/reference/operator/query/nin/

You are pushing the review object inside an object.
Instead do this:
await Seller.updateOne(
{ _id: seller_id },
{ $addToSet: { reviews: review } }
);

Map the nested data from other table using promise and async-await

I need the expert advice for this code. I need to know Is there any better way to solve this.
I am using the mongoose for db. I have a dataset like this:
Below is matchTable:
{
_id: 617bc0113176d717f4ddd6ce,
car: [],
status: true
},
{
_id: 617bc0113176d717f4ddd6cg,
car: [
{
aid: '5c1b4ffd18e2d84b7d6febcg',
}
],
status: true
}
And I have a Car table in which car name is there on behalf of id
like this
{ _id: ObjectId('5c1b4ffd18e2d84b7d6febce'), name: 'ford' },
{ _id: ObjectId('5c1b4ffd18e2d84b7d6febcg'), name: 'mitsubishi' },
So I want to make join the data from car table, so that response get name on behalf of aid.
Desired result will be like
{
_id: 617bc0113176d717f4ddd6ce,
car: [],
status: true
},
{
_id: 617bc0113176d717f4ddd6cg,
car: [
{
aid: '5c1b4ffd18e2d84b7d6febcg',
name: 'mitsubishi'
}
],
status: true
}
For that I have to merge the car table on matchTable. I have done this but I want to give some suggestion that is there any better way to do or is it fine. I need expert advice.
const getData = await matchTable.find(
{ status: true }
).lean().exec();
let dataHolder = [];
await Promise.all (
getData.map(async x => {
await Promise.all(
x.car.map(async y => {
let data = await Car.findOne(
{ _id: ObjectId(y.aid) },
{ name: 1 }
).lean().exec();
y.name = '';
if (data) {
y.name = data.name;
}
})
)
// If I return { ...x }, then on response it will return {}, {} on car column
dataHolder.push(x) //So I have chosen this approach
})
);
Please guide me if any better and efficient solution is there. Thanks in advance

You can make use of aggregation here.
const pipeline = [
{
$match : { status : true }
},
{
$unwind: '$matchtable',
},
{
$lookup: {
from: "cars",
localField: "car.aid",
foreignField: "_id",
as: "matchcars"
}
},
{
$addFields: {
"car.carName": { $arrayElemAt: ["$matchcars.name", 0] }
}
},
{
$group: {
_id: "$_id",
cars: { $push: "$matchcars" }
}
}
]
const result = await matchTable.aggregate(pipeline).exec();
Please make sure, aid field inside car array (in matchTable collection) is an ObjectId because its being matched to _id (which is an ObjectId) inside cars collection.

get $max of string

I am trying to aggregate data on my mongodb and to get some statistics regarding a collection,
i have a field called country and i need to get the one that exists the most
below attached is the current code,
consider my collection has 3 document:
{_id:1, country:"Italy"}
{_id:1, country:"Zimbabwe"}
{_id:1, country:"Italy"}
The expected output should be :Italy
But in reality i get Zimbabwe because it compares Z > I
visitSchema.statics.calcTotalVisits = async function (link) {
const stats = await this.aggregate([
{
$match: { link },
},
{
$group: {
_id: '$link',
sumDocs: { $sum: 1 },
topReferer: { $max: '$referer' },
topCountry: { $max: '$country' },
},
},
]);
console.log(stats);
};

Update value inside mongodb array object

I'm trying to update a value inside my array of objects.
Looking at the above mongoDB schema what I want is:
Find an expense with the ID match with the _id and need to update the fields with new ones from the req.body.
Just need to update the: expensesType, description, price and status.
The following code is what I tried to do.
First I need to match the right expense and it works fine but when I try to house.save() show me a message 'house.save is not a function'. So I think maybe I need to use a mongoDB function to get the result.
router.put("/editExpense/:id", ensureAuthenticated, (req, res) => {
var id = mongoose.Types.ObjectId(req.params.id);
House.find(
{ "expensesHouse._id": id },
{
members: 1,
name: 1,
description: 1,
address: 1,
type: 1,
user: 1,
userID: 1,
userType: 1,
expensesHouse: { $elemMatch: { _id: id } },
date: 1
}
).then(house => {
console.log(house);
expenseType = req.body.expenseType;
description = req.body.description;
price = req.body.price;
status = req.body.status;
house.save().then(() => {
req.flash("success_msg", "Expenses Updated");
res.redirect("/houses/dashboard");
});
});
});
****** UPDATED ******
After a search I found this updateOne and after adjusts, this is my final result but this way I delete every record..
router.put("/editExpense/:id", ensureAuthenticated, (req, res) => {
var id = mongoose.Types.ObjectId(req.params.id);
House.updateOne(
{ "expensesHouse._id": id },
{
members: 1,
name: 1,
description: 1,
address: 1,
type: 1,
user: 1,
userID: 1,
userType: 1,
expensesHouse: { $elemMatch: { _id: id } },
date: 1
},
{ $set: { "expensesHouse.expenseType": req.body.expenseType } }
).then(house => {
req.flash("success_msg", "Expenses Updated");
res.redirect("/houses/dashboard");
});
});
*********** RESOLUTION ***********
I just fixed the problem the way I show below.
House.updateOne(
{ "expensesHouse._id": id },
{
$set: {
expensesHouse: {
expenseType: req.body.expenseType,
description: req.body.description,
price: req.body.price,
status: req.body.status
}
}
}

You are really close to the answer the problem right now that you are having is syntax difference between find and UpdateOne
This is what Find expects, Check MongoDB docs
db.collection.find(query, projection)
This is what updateOne expects, Check Mongo docs
db.collection.updateOne(
<filter>,
<update>,
{
upsert: <boolean>,
writeConcern: <document>,
collation: <document>,
arrayFilters: [ <filterdocument1>, ... ],
hint: <document|string> // Available starting in MongoDB 4.2.1
}
)
See the Difference? Second parameter should be update not projection because Update one
returns
matchedCount containing the number of matched documents
modifiedCount containing the number of modified documents
upsertedId containing the _id for the upserted document.
A boolean acknowledged as true if the operation ran with write concern or false if write concern was disabled.
So Your code should be
House.updateOne(
{ "expensesHouse._id": id },
{ $set: { "expensesHouse.expenseType": req.body.expenseType } }
).then(house => {
req.flash("success_msg", "Expenses Updated");
res.redirect("/houses/dashboard");
});
});

House.findOneAndUpdate({userId : req.params.userId},
{ $set: { "expensesHouse.$[element].status": req.body.status } },
{ multi:true, arrayFilters: [{ "element.userID" : req.params.subUserId }], new:true })
Your Api reuquest consist of both the IDs (outer as well as inner) like /api/update/:userId/:subUserId

How to return an array of objects in GraphQL, possibly using the same endpoint as the one that returns a single object?

I am making a GraphQL API where I would be able to retrieve a car object by its id or retrieve all the cars when no parameter is provided.
Using the code below, I am successfully able to retrieve a single car object by supplying id as a parameter.
However, in the case where I would expect an array of objects i.e. when I supply no parameter at all, I get no result on GraphiQL.
schema.js
let cars = [
{ name: "Honda", id: "1" },
{ name: "Toyota", id: "2" },
{ name: "BMW", id: "3" }
];
const CarType = new GraphQLObjectType({
name: "Car",
fields: () => ({
id: { type: GraphQLString },
name: { type: GraphQLString }
})
});
const RootQuery = new GraphQLObjectType({
name: "RootQueryType",
fields: {
cars: {
type: CarType,
args: {
id: { type: GraphQLString }
},
resolve(parent, args) {
if (args.id) {
console.log(cars.find(car => car.id == args.id));
return cars.find(car => car.id == args.id);
}
console.log(cars);
//***Problem Here***
return cars;
}
}
}
});
Test queries and their respective results:
Query 1
{
cars(id:"1"){
name
}
}
Query 1 Response (Success)
{
"data": {
"cars": {
"name": "Honda"
}
}
}
Query 2
{
cars{
name
}
}
Query 2 Response (Fail)
{
"data": {
"cars": {
"name": null
}
}
}
Any help would be much appreciated.

A Car and a List of Cars are effectively two separate types. A field cannot resolve to a single Car object one time, and an array of Car object another.
Your query is returning null for the name because you told it the cars field would resolve to a single object, but it resolved to an array instead. As a result, it's looking for a property called name on the array object and since one doesn't exist, it's returning null.
You can handle this in a couple of different ways. To keep things to one query, you can use filter instead of find and change the type of your query to a List.
cars: {
type: new GraphQLList(CarType), // note the change here
args: {
id: {
type: GraphQLString
},
},
resolve: (parent, args) => {
if (args.id) {
return cars.filter(car => car.id === args.id);
}
return cars;
}
}
Alternatively, you could split this into two separate queries:
cars: {
type: new GraphQLList(CarType),
resolve: (parent, args) => cars,
},
car: {
type: CarType,
args: {
id: {
// example of using GraphQLNonNull to make the id required
type: new GraphQLNonNull(GraphQLString)
},
},
resolve: (parent, args) => cars.find(car => car.id === args.id),
}
Check the docs for more examples and options.